Portable flashlight having circuit testing means and a rotating telescoping head portion with cut-out for exposing a test contact



June 21, 1966 R. o. FARISS 3,257,610

PORTABLE FLASHLIGHT HAVING CIRCUIT TESTING MEANS AND A ROTATING TELESCOPING HEAD PORTION WITH CUT-OUT FOR EXPOSING A TEST CONTACT Filed Aug. 27. 1964 INVENTOR. RAYMOND O. FARISS which electrical work is to take place.

United States Patent 3 251 610 PORTABLE FLAsrrLitinTnA /mc cracurr TEST- llNG MEANS AND A noTAriNe rarnscoruso HEAD PORTHUN wrrn cor-our non ExPos- ING A Taste corsrxcr Raymond G. Fariss, 327 4th St., Santa Monica, Calif. Filed Aug. 27, 1964, Set. No. 392,653

4 Claims. (Cl. 324-53) This invention relates generally to flashlights and more particularly to an improved portable type battery 0perated flashlight for use by electricians.

In electrical repair work, it is common practice for electricians to carry a flashlight to illuminate areas in For example, many fuse boxes are poorly illuminated in their interiors. In other instances, it may be desirable to read the electrical ratings of various motors and the like which are in dark areas of a home. In addition, it is frequently necessary in electrical repair work for the electrician to test fuses, light bulbs, the electrical continuity of electrical wiring and the like. Normally, there is no convenient means for effecting such continuity tests and as a consequence, the electrician will simply replace fuses with fuses in his box which he knows to be in proper working order. The same situation obtains with light bulbs and also electrical wiring.

With the foregoing in mind, it is a primary object of this invention to provide a flashlight which incorporates simple means for enabling an electrician to test for continuity so that fuses, light bulbs, electrical wiring and the like may be very easily and quickly tested to ascertain whether they are faulty.

Another object of this invention is to provide an improved flashlight meeting the foregoing objects which is of the same size and general character of normal flashlights and may be operated in the same manner as a normal flashlight so that no appreciable change in the flashlight is evident over conventional flashlights and so that the electrician need not be burdened with any additional equipment over that which he normally carries.

Still another object is to provide an improved flashlight meeting the foregoing objects which does not incorporate expensive additions nor require appreciably expensive retooling of conventional equipment for manufacturing the flashlight.

Still another important object of this invention is to provide a flashlight capable of continuity testing of various foreign elements and also capable of testing continuityof high resistance elements, all without the need of any auxiliary power source other than that incorporated in the flashlight itself.

Briefly, these and other objects and advantages of this invention are attained by providing a conventional type flashlight in the form of a casing with a lead structure coupled thereto. The casing incorporates conventional battery means and the head structure includes a reflector and bulb. The casing may also be provided with the conventional on-off switch for the flashlight.

.In accordance with the present invention, the flashlight is also provided with a first contact preferably on the side of the casing and in exposed condition. A second contact is also provided on the casing spaced a given distance from the first contact in such a manner that a foreign element such as a fuse or auxiliary light bulb may be bridged across the first and second contacts. These first and second contacts are electrically connected in series with 'ice the batteries and light bulb of the flashlight so that bridging of the exposed contacts will illuminate the flashlight bulb and thus indicate continuity.

In accordance with a preferred embodiment of the invention, the second contact is disposed beneath a portion of the head structure, the head structure itself including a cut-out such that a small rotation of the head structure will expose the second contact. By this arrangement, there is no possibility of inadvertently having the first and second contacts shorted out if the flashlight is set on a metal table or the like.

In accordance with a still further feature of the invention, the circuitry between the contacts and battery of the flashlight includes a sensitive relay which is responsive to small currents normally of not suflicient magnitude to illuminate the light bulb in the flashlight. This relay in turn closes a circuit directly across the light bulb and battery so that if the relay is energized, the flashlight bulb will be illuminated thereby indicating that a small current at least was received in the relay. This arrangement permits .high resistance foreign elements such as conventional household light bulbs to be tested by the flashlight.

A better understanding of the invention will be had by now referring to one embodiment thereof as illustrated in the accompanying drawings, in which:

FIGURE 1 is a cut-away perspective view of the improved flashlight of this invention also showing in exploded positions, various foreign members or elements capable of being tested by the flashlight;

FIGURE 2 is a simple schematic circuit diagram of a first circuit embodiment of the flashlight; and,

FIGURE 3 is a simple schematic diagram illustrating a second circuit embodiment of the flashlight.

Referring first to FIGURE 1, there is shown a flashlight casing 10 including a suitable head structure 11 coupled to its upper end. Normally, the head structure 11 incorporates a bulb 12 and is in threaded engagement with the upper end of the casing 10, the lower portion of the head structure being telescoped over the upper end of the casing.

A conventional switch means as shown at 13 may be disposed on the side of the casing 10 for completing a circuit between batteries 14 incorporated within the casing 10 to the light bulb 12.

The elements described above for the flashlight are entirely conventional. In accordance with the instant invention, there is provided a first elongated exposed contact 15 on the casing 10. Also provided is a second contact 16 on the upper end of the casing in a position to be eclipsed by the lower telescoping portion of the head structure 11. This lower telescoping portion as shown includes a cut-out 17 such that the head structure 11 may I be rotated in the direction of the arrow 18 to position the cut-out 17 over the contact 16 and thus expose this contact.

In the operation of the flashlight as described thus far, the flashlight itself may be used in a conventional manner, the bulb being illuminated by operation of the switch 13. If it should now be desired to test the continuity of some foreign element such as wiring, the first and second contacts 15 and 16 are electrically bridged by the element. These contacts, as will become clearer as the description proceeds, are connected in series between the batteries 14 and light bulb 12 so that a circuit will be completed by the bridging thereof provided that the bridging member is electrically continuous. The

3 light bulb 12 will thus be illuminated to indicate continuity.

As an example, there is shown an electrical household cord 19 incorporating wires 20 and 21 connecting respectively to a plug 22 and prongs 23 and 24. To test the continuity of the wires, the prong 23 may be disposed in engagement with the first contact and the wire then touched to the second contact 16. If the wire is continuous, the light bulb 12 will be illuminated. The same procedure may then be repeated for the prong 24 and the wire 21. In this respect, it will be clear that it is an easy manner to determine which wire corresponds to which prong, assuming that both are continuous should the wire be twisted or covered by a sheaving in which it is not possible to associate one wire with one particular prong.

In FIGURE 1 there is also shown a cylindrical type fuse 25 having end contacts 26 and 27. To test this fuse, it is only necessary to dispose the contact 26 against the second contact 16 on the flashlight casing and the contact 27 on the elongated first contact 15. By making this first contact 15 elongated as shown, variouslength fuses may readily be accommodated. Again, if the fuse is not faulty, a circuit will be completed through the contacts to the light bulb 12.

Finally, FIGURE 1 illustrates a'conventional household light bulb 28 including the usual threaded contact portion 29 and tip 30. Household light bulbs of this type have very high resistance filaments and normally bridging of the contact areas 29 and 30 to the contacts 15 and 16 would not result in illumination of the bulb 12 were a simple direct series connection to the bulb effected. Accordingly, the present invention contemplates a relay circuit which is responsive to very small currents for completing the circuit to the light bulb so that bulbs such as indicated 28 may readily be tested.

The foregoing will become clear by referring to the simple schematic circuit diagrams of FIGURES 2 and 3. In the circuit diagram of FIGURE 2, a first terminal of the flashlight bulb 12 is indicatedat 31 and the tip or second terminal of the light bulb is indicated at 32. As shown, the terminal 31 connects through a lead 33 and the normal flashlight switch 13 to a lead 34 and thence to a lead 35 to one side of the battery 14. This side of the battery 14 is also connected by a lead 36 to the first contact 15. The other light bulb terminal 32 connects through a lead 37 to the other side of the battery 14. The second contact 16 connects by a lead 38 to the terminal or threaded portion 31 of the light bulb 12.

Disregarding for the moment the switch 13 and associated electrical leads 33 and 34, it will be noted that the contacts 15 and 16 are effectively connected in series with the battery 14 and light bulb 12. It will thus be evident that if these contacts 15 and 16 are bridged, a circuit will be completed from the battery 14 to the light bulb to illuminate the same. Considering now the circuit with the switch 13 in place, it will be evident that effectively the switch 13 is connected in parallel with the contacts 15 and'16 so that closing of the switch will serve to light the bulb 12 regardless of whether or not the contacts 15 and 16 are shorted. The flashlight may thus be used in a conventional manner.

The circuit of FIGURE 2 may be incorporated in a flashlight and serves to enable testing of the continuity of fuses, electrical wires, and the like." In the event, however, that it is desired to test relatively high resistance foreign elements such as the light bulb 28, it is necessary to modify the circuit of FIGURE 2.

FIGURE 3 shows such a modified circuit wherein various like elements are designated by the same numerals. The only addition to the circuit of FIGURE 3 is the provision of a lead 39 from the contact 16 including a sensitive relay coil 40, the other side of which is connected by a lead 41 to the battery lead 37. Also included is a lead 42 connecting from the threaded portion 4 31 of the light bulb 12 through a relay switch arm 43 and thence to a lead 44 connecting to the first contact 15. The switch arm 43 is responsive to energization of the relay coil 40 to close and thus connect the threaded portion of the light bulb 31 directly to the first contact 15 and thus to the other side of the battery.

In the operation of the circuit of FIGURE 3, a foreign element even if it has a high resistance bridging the first and second contacts 15 and 16 will provide a small current through the relay coil 40 which is sufficient to throw the relay switch arm 43 and thus complete a circuit through the contact 15 between the battery 14 and bulb 12, thereby illuminating the same. Thus, lighting of the bulb 12 will occur whenever the relay coil 40 draws sulficient current to become energized. When a light bulb such as the bulb 28 of FIGURE 1 thus bridges the contacts 15 and 16, even though it has a relatively high resistance, there will still result enough current through the relay coil 40 to energize the same and close the switch arm 43, even though this current in and of itself would not be sufficient to light the bulb 12. However, with the arm 43 closed, there is provided a direct circuit between the bulb 12 and battery 14 so that the bulb will light.

It should also be evident that the circuit of FIGURE 3 may be employed for straight continuity testing, the same as the circuit of FIGURE 2.

From the foregoing description, it will be evident that the present invention has provided a greatly improved flashlight which is of considerable value to electricians and similar maintenance men when working on electrical equipment. It will be evident to those skilled in the art that the principles of the invention are applicable to different types of flashlights other than the conventional cylindrical type shown. Further, it should be understood that any equivalent current responsive switching device such as a transistor or diode may be substituted for the relay coil 40 and switch arm 43. The invention is therefore not to be thought of as limited to the exact embodiment set forth merely for illustrative purposes.

What is claimed is:

1. A flashlight comprising: a casing incorporating battery means; a head structure telescoped over and coupled to the upper end of said casing and incorporating a light bulb; an exposed first conducting contact surface on said casing; a second contact surface on the upper portion of said casing beneath the portion of said head structure telescoped thereover, said head structure including a cutout in its telescoping portion such that rotation thereof exposes said second contact through said cut-out; and connecting means for connecting said first and second contacts with said battery means and light bulbs so that shortcircuiting of said first and second contacts lights said light bulb whereby fuses and the like may be tested by bridging the same across said first and second contacts.

2. A flashlight according to claim 1, including switch means on the side of said casing connected in parallel with said first and second contacts whereby said bulb may be illuminated by closing of said switch means.

3. A flashlight according to claim 1, in which said connecting means includes a current responsive switching device connected between said second contact and one terminal of said battery means, one terminal of said light bulb being connected to said first contact in response to current through said current responsive switching device, the other terminal of said light bulb connecting to said one terminal of said battery means, and the other terminal of said battery means connecting to said first contact whereby energization of said current responsive device to close the circuit to said light bulb illuminates said bulb, said device being responsive to a current less than that necessary to light said light bulb whereby the continuity of high resistance electrical devices may be tested by bridging the same across said first and second contacts.

UNITED References Cited by the Examiner STATES PATENTS Chase 340-251 Zachae 324-53 Borsody 324-53 Palmer 324-5 3 6 6/1958 Chandler et a1. 324-53 6/1960 Gelli 324-251 X 10/1961 Ciardiello 324-53 10/ 1962 Rosenstrach 324-53 3/1965 Behr 317-18 X FOREIGN PATENTS 12/ 1951 France.

4/1947 Great Britain.

10 WALTER L. CARLSON, Primary Examiner.

G. R. STRECKER, Assistant Examiner. 

1. A FLASHLIGHT COMPRISING: A CASING INCORPORATING BATTERY MEANS; A HEAD STRUCTURE TELESCOPED OVER AND COUPLED TO THE UPPER END OF SAID CASING AND INCORPORATING A LIGHT BULB; AN EXPOSED FIRST CONDUCTING CONTACT SURFACE ON SAID CASING; A SECOND CONTACT SURFACE ON THE UPPER PORTION OF SAID CASING BENEATH THE PORTION OF SAID HEAD STRUCTURE TELESCOPED THEREOVER, SAID HEAD STRUCTURE INCLUDING A CUTOUT IN ITS TELESCOPING PORTION SUCH THAT ROTATION THEREOF EXPOSES SAID SECOND CONTACT THROUGH SAID CUT-OUT; AND CONNECTING MEANS FOR CONNECTING SAID FIRST AND SECOND CONTACTS WITH SAID BATTERY MEANS AND LIGHT BULBS SO THAT SHORTCIRCUITING OF SAID FIRST AND SECOND CONTACTS LIGHTS SAID LIGHT BULB WHEREBY FUSES AND THE LIKE MAY BE TESTED BY BRIDGING THE SAME ACROSS SAID FIRST AND SECOND CONTACTS. 